WBBSE For Class 9 Physical Science And Environment Chapter 5 Energy In Action, Work, Power And Energy MCQS

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Chapter 5 Energy In Action, Work, Power And Energy MCQs

Question 1. The rate of doing work is called

  1. Velocity
  2. Energy
  3. Power
  4. Force

Answer: (3) Power

Question 2. The unit of energy in SI system is

  1. Erg
  2. Watt
  3. Horse power
  4. Joule

Answer: (4) Joule

Read And Learn More WBBSE Solutions For Class 9 Physical Science And Environment MCQS

Question 3. One watt is equal to

  1. 1 erg/s
  2. 1 g.cm/s
  3. 1 kg.m/s
  4. 1 joule/s

Answer: (4) 1 joule/s

Question 4. One horsepower is equal to

  1. 500 W
  2. 1000 W
  3. 746 W
  4. 764 W

Answer: (3) 746 W

WBBSE For Class 9 Physical Science And Environment Chapter 5 Energy In Action, Work, Power And Energy MCQS

WBBSE Class 9 work power and energy MCQs with answers

Question 5. Kilowatt is the unit of

  1. Energy
  2. Work done
  3. Power
  4. Force

Answer: (3) Power

Question 6. ln case of negative work, the angle between force and displacement is

  1. 0°
  2. 45°
  3. 90°
  4. 180°

Answer: (4) 180°

Question 7. In a tug-of-war, work done by the losing team is

  1. Positive
  2. Negative
  3. Zero
  4. None of these

Answer: (2) Negative

Work power and energy multiple choice questions for WBBSE Class 9

Question 8. The work done on an object does not depend upon the

  1. Displacement
  2. Initial velocity of the object
  3. Force applied
  4. Angle between force and displacement

Answer: (2) Initial velocity of the object

Question 9. Which one of the following is not a unit of energy?

  1. Kilowatt
  2. Joule
  3. Newton-metre
  4. Kilowatt-hour

Answer: (4) Kilowatt

Question 10. When an object falls freely under gravity, then its total energy

  1. Increases
  2. Decreases
  3. Remains constant
  4. First increases and then decreases

Answer: (3) Remains constant

Question 11. When a body moves in a circular path, everything remains unchanged except

  1. Acceleration
  2. Kinetic energy
  3. Speed
  4. Retardation

Answer: (2) Kinetic energy

Important work and energy questions for Class 9 Physical Science

Question 12. A body when raised from the floor to the top of a table, the work done depends on

  1. Weight of the body
  2. Time needed to raise it
  3. Velocity of the body
  4. Acceleration of the body

Answer: (1) Weight of the body

Question 13. A person while walking along a-road carrying a bag in hand, he does

  1. Not do work on the bag
  2. Work on the bag
  3. Work on the bag if the bag be light
  4. Work on the bag if the bag be heavy

Answer: (1) Not do work on the bag

Question 14. A mechanical system tends to attain the position of 

  1. Maximum kinetic energy
  2. Minimum kinetic energy
  3. Minimum potential energy
  4. Maximum potential energy

Answer: (3) Minimum potential energy

Question 15. A body of mass m when raised from.a depth h below the earth’s surface to a position h distance above the earth, the change of potential energy will be

  1. 2 mgh
  2. Zero
  3. mgh
  4. 3 mgh

Answer: (3) mgh

WBBSE Class 9 Physical Science MCQs on energy in action

Question 16. Newton meter is the unit of

  1. Work in-SI
  2. Power in SI
  3. Power in SI
  4. Work in CGS

Answer: (1) Work in SI

Question 17. Two bodies of masses 1 g and 4 g move with equal kinetic energy. Ratio of the magnitude of their momenta is

  1. 4:1
  2. \(\sqrt{2}\):1
  3. 1:2
  4. 1:16

Answer: (3) 1:2

Question 18. On application of an external force on a moving body, a body is retarded. Work done by the body is

  1. Negative
  2. Positive
  3. Zero
  4. Half

Answer: (1) Negative

Question 19. Due to winding of spring, a clock acquires

  1. Kinetic energy
  2. No energy
  3. Elastic potential energy
  4. Gravitational potential energy

Answer: (3) Elastic potential energy

Question 20. To obey the law of conservation of linear momentum during collision a condition is

  1. External force is 0
  2. Time of collision is negligible
  3. No internal force
  4. External force is maximum

Answer: (1) External force is 0

Solved MCQs on work, power, and energy for WBBSE Class 9

Question 21. A raindrop of radius R fell on ground from a height h. Work done by the gravitational force is proportional to

  1. \({R}^{}\)
  2. \(\sqrt{R}\)
  3. \({R}^{3}\)
  4. \({R}^{2}\)

Answer: (3) \({R}^{3}\)

Question 22. A body is moved from a point A to point B over a rough surface that possesses friction due to which x work is done. The pedy moves back from B to A on the same surface. Total work done will be

  1. Zero
  2. x
  3. 2x
  4. 3x

Answer: (3) 2x

Question 23. Which pair of physical quantities have same unit?

  1. Force and work
  2. Work and energy
  3. Power and force
  4. Work and power

Answer: (2) Work and energy

Question 24. Increase of kinetic energy equals

  1. Increase of mass
  2. Work done
  3. Increase of power
  4. Increase of velocity

Answer: (2) Work done

Question 25. Two bodies of different masses have equal kinetic energy. Momentum possessed by

  1. The body of less mass is larger
  2. The body of larger mass is larger
  3. Both the bodies are equal
  4. The body of larger velocity is larger

Answer: (2) The body of larger mass is larger

Question 26. Work is done when the point of application of force moves

  1. Perpendicular to the force
  2. In the direction of force
  3. In any direction
  4. In the direction perpendicular to force

Answer: (2) In the direction of force

Law of conservation of energy MCQs Class 9 WBBSE

Question 27. Water reserved in a dam possesses

  1. Kinetic energy
  2. Potential energy
  3. Both potential and kinetic energies
  4. No energy

Answer: (2) Potential energy

Question 28. A person performs 300 J work in 1.5 hr. Another person does 1500 J in 100 hr. The power of

  1. 1st person is greater
  2. 2nd person is greater
  3. Both the person are equal
  4. Both are zero

Answer: (1) 1st person is greater

Question 29. SI unit of energy is

  1. Joule
  2. Erg
  3. Dyne
  4. Newton

Answer: (1) Joule

Question 30. The potential energy of a boy is maximum when he is

  1. Sitting on the floor
  2. Standing on the floor
  3. Sleeping on the floor
  4. Sitting on a chair

Answer: (2) Standing on the floor

Question 31. Water stored in a dam possesses

  1. KE
  2. PE
  3. Electric energy
  4. No energy

Answer: (2) PE

Question 32. The kinetic energy of an object is K. If its mass is reduced to half, then its kinetic energy will be

  1. K
  2. 2K
  3. K/2
  4. K/4

Answer: (3) K/2

Question 33. The work done on an object does not depend upon the 

  1. Force applied
  2. Initial velocity
  3. Displacement
  4. Angle between force and displacement

Answer: (2) Initial velocity

Question 34. In case of negative work, the angle between force and displacement is

  1. 0°
  2. 45°
  3. 90°
  4. 180°

Answer: (4) 180°

Question 35. In a tug-of-war, work done by the losing team is

  1. Zero
  2. Positive
  3. Negative
  4. None of these

Answer: (3) Negative

Best multiple choice questions on work power and energy for WBBSE Class 9

Question 36. A stone is thrown vertically upwards. It comes to rest momentarily at the highest point. What happens to its kinetic energy?

  1. It is converted into elastic potential energy
  2. It is converted into gravitational potential energy
  3. It is converted into chemical energy
  4. It is completely destroyed

Answer: (2) It is converted into gravitational potential energy

Question 37. A force of 100 N acting on a body 1000 J work. The distance through which the body is displaced is

  1. 5m
  2. 10 cm
  3. 10m
  4. 55cm

Answer: (2) 10 m

Question 38. When electric current passes through an electric bulb, electric energy is converted into

  1. Heat energy only
  2. Light energy only
  3. Both heat and light energy
  4. Both light and chemical energy

Answer: (3) Both heat and light energy

Question 39. What type of energy a raised hammer possesses?

  1. Kinetic energy
  2. Potential energy
  3. Gravitational energy
  4. No energy

Answer: (2) Potential energy

Question 40. What is the absolute unit of work in SI system?

  1. 1 kg-m
  2. 1 joule
  3. 1 erg
  4. 1 dyne

Answer: (2) 1 joule

Question 41. What is the relation between power and force?

  1. Power = force x velocity
  2. Velocity = force x power
  3. Force = power x velocity
  4. Power = force/2

Answer: (1) Power = force x velocity

Question 42. What is the amount of work performed by a person on the weight w that he carries and moves horizontally through a distance d?

  1. No work is done
  2. Work done = w xd
  3. Work done = w ÷ d
  4. Work done \(=\frac{d}{w}\)

Answer: (1) No work is done

Question 43. The dimension of energy is

  1. \(\left[\mathrm{ML}^2 \mathrm{~T}^{-2}\right]\)
  2. \(\left[\mathrm{M}^2{L}^2 \mathrm{~T}^{3}\right]\)
  3. \(\left[\mathrm{ML}^2 \mathrm{~T}^{3}\right]\)
  4. \(\left[\mathrm{ML}^3 \mathrm{~T}^{2}\right]\)

Answer: (1) \(\left[\mathrm{ML}^2 \mathrm{~T}^{-2}\right]\)

Question 44. All energies are transformed ultimately into

  1. Heat energy
  2. Kinetic energy
  3. Sound energy
  4. Electric energy

Answer: (1) Heat energy

Question 45. Which one is a scalar quantity?

  1. Force
  2. Displacement
  3. Work
  4. Velocity

Answer: (3) Work

Question 46. If the velocity of a body is doubled then kinetic energy will be

  1. Same
  2. Doubled
  3. Four times
  4. Halved

Answer: (3) Four times

Question 47. Work done in unit time is known as

  1. Power
  2. Energy
  3. Force
  4. Velocity

Answer: (1) Power

Question 48. 1 kilowatt =

  1. \(\frac{2}{3}\) HP
  2. \(\frac{4}{3}\) HP
  3. \(\frac{7}{3}\) HP
  4. \(\frac{1}{3}\) HP

Answer: (2) \(\frac{4}{3}\) HP

WBBSE Class 9 Physical Science kinetic and potential energy MCQs

Question 49. What is the unit of kinetic energy is SI system?

  1. Erg
  2. HP
  3. Joule
  4. Dyne

Answer: (3) Joule

Question 50. 1 mega-watt =

  1. \({10}^3\) watt
  2. \({10}^4\)watt
  3. \({10}^6\)watt
  4. \({10}^2\) watt

Answer: (3) \({10}^6\)watt

Question 51. Kilogram-metre is the unit of

  1. Energy
  2. Power
  3. Work
  4. Velocity

Answer: (3) Work

Question 52. The dimension of power is

  1. \(\left[\mathrm{ML}^2 \mathrm{~T}^{-3}\right]\)
  2. \(\left[\mathrm{M}^2{L}^2 \mathrm{~T}^{-2}\right]\)
  3. \(\left[\mathrm{ML}^3 \mathrm{~T}^{3}\right]\)
  4. \(\left[\mathrm{ML}^2 \mathrm{~T}^{3}\right]\)

Answer: (1) \(\left[\mathrm{ML}^2 \mathrm{~T}^{-3}\right]\)

Question 53. 1 watt =

  1. \({10}^5\) erg/sec
  2. \({10}^6\) erg/sec
  3. \({10}^7\) erg/sec
  4. \({10}^8\) erg/sec

Answer: \({10}^7\) erg/sec

Question 54. What is the practical unit of power in CGS system?

  1. Erg
  2. Watt
  3. Joule
  4. Newton

Answer: (2) Watt

 

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